Kesha is clawing back at Sen. J.D. Vance over his disdain for "childless cat ladies" -- she's wearing his insult as a badge of honor, and firing some expletives his way ... just for good measure.

The "Joyride" singer rolled up to LAX Thursday, and a photog asked her about Donald Trump's running mate, who's sparked outrage with his past comments about childless women running the Democratic party.

Kesha starts booing the moment the photog utters Vance's name, quickly adding a "F*** that man!"

As you know, Vance is facing tons of backlash from a resurfaced 2021 clip with Tucker Carlson.

In the interview, Vance tells Tucker women like VP Kamala Harris are "childless cat ladies who are miserable at their own lives" and have "no direct stake" in the future of America.

It's funny, Kesha says Vance is actually right ... declaring childless cat ladies are indeed running the country, "And this is what it looks like, bitch!!!"

Kesha goes on to say Vance's view is incredibly sexist, and throws her support behind Harris.